The present invention relates to apparatus for the gasification of fine-grain coal under pressure in a reactor. The latter has an exit which is connected to a waste-heat boiler for cooling the generated gas. The waste-heat boiler has a radiation section and heat exchange surfaces arranged downstream.
In such apparatus there is the danger that the heating surfaces of the waste-heat boiler contaminate quickly by the ash contained in the coal. This contamination deteriorates the heat transfer and, consequently, the cooling of the gas. A known prior art plant has a fire tube boiler which follows the radiation section of the waste heat boiler. In such fire tube boilers the heat of the gases can be reduced only to the temperature of the saturated stream generated in the fire tube boiler. This is the reason why the generated gas leaves the waste heat system at a relatively high temperature.